Text 4 Turning oil rigs into reefs saves money and marine life.Yet many greens oppose it.When an offshore well stops producing oil,what should be done with the rig?One option is to haul it ashore,break it up and recycle it.This is expensive.For a big,deep-water oil or gas platform,it can cost S200m.Just hiring a derrick barge massive enough to do the job can cost$700,000 a day.But there is an altemative:simply leave most of the structure where it is.That is what you would expect a greedy oil firm to do:despoil the ocean just to save a lousy few million dollars.The surprise is,the cheap option may actually be greener.More than 490 platforms in American waters have become reefs in the past three decades.The federal Bureau of Safety and Environmental Enforcement urges states to issue reefing permits.State coffers gain:oil firms typically hand over half the money they save by reefing.Those savings vary greatly.Small platforms in shallow waters can often be removed for$lOm,but sometimes for as little as$lm,according to DecomWorld,a consultancy.But for states with lots of offshore oil rigs,the windfalls soon add up.Mississippi pocketed an average of$625,000 for each of the 12 permits it has issued,according to Melissa Scallan of the state's Department of Marine Resources.Louisiana's take has averaged$270,000 per reefing-and the state has seen 336 0f them,says Mike McDonough of the Louisiana Department of Wildlife and Fisheries.Far bigger savings arc possible in the deep waters off California.Four years ago the Golden State passed a law allowing reefing.Operators are Ioth to estimate costs publicly,but the Tulane University Energy Institute reckons that reefing the state's 27 platforms could save$2 billion.A platform or two could be retired as early as next year,though rising oil prices may mean they keep pumping longer.The debate is likely to intensify.In the Gulf of Mexico some 400 platforms are now being decommissioned each year.Divers and many fishermen want more to be reefed;shrimpers complain that reefs prevent them from dragging nets across parts of the ocean floor.In Califomia operators must decide quickly if they wish to turn redundant rigs into reefs.Until 2017 firms can keep 45%of the savings.After that the figure falls t0 35%until 2023;then it drops to just 20%.For now,the evidence suggests that reefing is a rare policy.It is both eco-friendly and pays for itself.
It can be inferred from the text that will save least from rectifying_____
A.the state authority
B.shoal waters
C.deep waters
D.gold coast